Wood options for boat decking

[Rick M]

My aluminum boat needs a new floor and I'm mulling my options. Looking for opinions or experience as boat flooring is new to me. Boat is a 14.5' Grumman aluminum fishing boat, so this is a relatively simple project. The original floor was plywood and carpet, rotted away now. Previous owner covered it with painted plywood which I pulled out. I don't want to replace it with plywood because -- well plywood is complicated in aluminum boats.

Short version: I'm debating cedar or composite decking. They are similar enough in cost, either should last 10 years or more. There are other woods I'd consider if I found a good deal on them.

What should I use and where should I buy it?

 

[CrealBilly]

My aluminum boat needs a new floor and I'm mulling my options. Looking for opinions or experience as boat flooring is new to me. Boat is a 14.5' Grumman aluminum fishing boat, so this is a relatively simple project. The original floor was plywood and carpet, rotted away now. Previous owner covered it with painted plywood which I pulled out. I don't want to replace it with plywood because -- well plywood is complicated in aluminum boats.

Short version: I'm debating cedar or composite decking. They are similar enough in cost, either should last 10 years or more. There are other woods I'd consider if I found a good deal on them.

What should I use and where should I buy it?

View attachment 16193

I would think weight and rot resistance would be a factor in your decision - yes?

Maybe the Fountain of Youth isn't a fountain at all. Maybe it's a way of looking at things. A way of thinking.

 

[Canuck]

If you decide on cedar, check out Scott Smith's ERC stash.

I picked up about 50 board feet from him last week to use for a raised garden and after planing, I wished that I had used it on a more deserving project. Very pretty stuff, very little sap wood and a terrific odor!

Price was great too.

Wayne

 

[Raymond]

OK, I understand wanting to use cedar or the composite decking material but why are you ruling out marine grade plywood? just wondering, I have never used marine grade plywood before but I have heard of people using it.

 

[smallboat]

marine ply
or
cypress is nice and light


also lots of good info on the WEST System website as well

 

[gazzer]

What makes plywood marine grade is the type of glue they use to laminate. This means that lot of marine plywood is not all that rot resistant. It won't delaminate, but it may rot over time. For a boat that is stored dry, this isn't all that significant, though. I'd use cedar because it is inexpensive, looks good, and will last a long time.

 

[cyclopentadiene]

Another vote for cypress over marine grade plywood. I have used the plywood approach along with finishing with spar urethane for skateboard ramps. This is supposed to be very water resistant and is for about 2 years, then it fails quickly at the screw holes. Another think to consider is using at a minimum coated screws as others rust and bleed into the wood.

 

[Jim M.]

If plywood is out, try using strong, heavy woods like locust and white oak for framing and structural members, and lighter weight woods like cedar and cypress for planking. Jim

 

[smallboat]

For what its worth I built a sailing dinghy 29 years ago from AC exterior ply and coated it with epoxy.
I didn't spend the $ for WEST epoxy on that one since it was a quick and dirty build. Don't recall the brand I used.
Nevertheless I'm still sailing the boat with a minimum of maintenance.

Dry stored so your mileage may vary.

I would think any decent wood treated with marine epoxy would serve your purpose.
My vote for ply is based on the uniform strength and higher strength to weight.
Anything else you choose will necessitate more seams and probably more framing structure.
If you're inclined towards fasteners (rather than glued structures) then you add the issue of inviting moisture into the interior of the wood.

You haven't stated why you are ruling out ply for your project.
If its simply the poor performance of the original, I'd suggest further research.
A properly constructed wood deck should be strong, light and very durable.

Unfortunately some builders treat the deck as something to hold up the carpet.

 

[SubGuy]

Cypress is a wood grown in water. It's at home there...

 

[nn4jw]

Regardless of what wood you end up using resist any temptation to apply any type of carpeting at all. No matter what the manufacturers state, all carpeting will wick water, hold it to a certain degree and eventually rot any wood it's in contact with. It will mildew.

The one boat I owned that had carpeting complete rotted out inside of 10 years. And I took care of it all those years.

 

[chris_goris]

My aluminum boat needs a new floor and I'm mulling my options. Looking for opinions or experience as boat flooring is new to me. Boat is a 14.5' Grumman aluminum fishing boat, so this is a relatively simple project. The original floor was plywood and carpet, rotted away now. Previous owner covered it with painted plywood which I pulled out. I don't want to replace it with plywood because -- well plywood is complicated in aluminum boats.



Short version: I'm debating cedar or composite decking. They are similar enough in cost, either should last 10 years or more. There are other woods I'd consider if I found a good deal on them.

What should I use and where should I buy it?

View attachment 16193

I dont think I would use composite decking, the stuff is STUPID heavy!

 

[JimD]

My boat was built in 1990 and still has the original plywood floor. It is carpeted. I have kept a cover on it as did the former owner. But no cover works perfectly so the floor gets wet sometimes. There is one or two soft spots near the edge but the floor is basically fine. I don't know exactly what kind of plywood it is.

If I need to replace the floor in mine I will use 1/2 pressure treated plywood. It won't rot. I used 3/4 PT plywood for the floor of my trailer and it has survived the weather for over 10 years now. It isn't covered.

 

[Skymaster]

pressure treated ply most bang for your dollar. very durable, SEAMLESS install if you measure well

 

[Rick M]

So cedar vs cypress -- both weather resistant, both seem ideal. I suppose it boils down to best looking for the best price. Clear would be preferable.


Using plywood, especially treated plywood with aluminum, is complicated on an open to weather boat. The plywood really should be encased in epoxy and there is no advantage to the extra time and expense unless you want carpet or a plastic-like floor. In any case, I've already decided on wood.

 

[CrealBilly]

I think I would go with the heartwood of cypress. I never had much luck with treated plywood it likes to curly up like a pretzel on me. If I dont put a ton of fasteners in it.

Maybe the Fountain of Youth isn't a fountain at all. Maybe it's a way of looking at things. A way of thinking.

 

[Dave Richards]

Are you replacing the stringers below the sole? If so, make sure you put in limber holes (notches in the bottoms of the stringers) so water that inevitably gets into the bilge can find its way to the lowest point for removal. Since you'll have exposed end grain in those holes, seal the wood with epoxy or something. They won't be easy to repair later.

Also make the sole so you can remove sections so you can get at the hull for cleaning and repair when needed. I would make the section over the lowest point very easy to remove so you can get at water that may accumulate. You might be pulling the transom plug but that won't drain out all of the water and dirt in the water will settle out before you can drain the boat anyway.

 

[Rick M]

Once the old floor is completely out, I can make a more complete plan. Leaving the original stringers as they seem to be fine. There is foam under the old floor except in a center channel which allows water to drain from the bow. I will probably remove the boxes on the inside while replacing the floor and put them back after, they stiffen the sides.

Been reading some cypress vs cedar articles. Many people claiming that modern cypress doesn't have enough oils and isn't as rot resistant as the old stuff, also that cypress will mildew, but it is a little harder than cedar. So I'm going back and forth but cedar is slightly in the lead. I still have a few days to make up my mind. My workshop has a small cedar porch I built ~10 years ago and it's still going strong.

 

[redknife]

Been reading some cypress vs cedar articles. Many people claiming that modern cypress doesn't have enough oils and isn't as rot resistant as the old stuff, also that cypress will mildew, but it is a little harder than cedar. So I'm going back and forth but cedar is slightly in the lead. I still have a few days to make up my mind. My workshop has a small cedar porch I built ~10 years ago and it's still going strong.

I believe that modern cedar has some of the same issues as modern cypress in terms of worse rot resistance compared to old cedar lumber. Of course these are are generic statements and a specific wood source may have higher quality cedar or cypress.

 

[Rick M]

I've learned a lot about rot resistance on this project. Mostly that rot resistance is based on heartwood only and that sapwood is not considered rot resistant regardless of species.
- Rick M, sent via Tapatalk